The present invention relates generally to methods of preserving cooked egg products. More specifically, the present invention concerns preservation of a cooked egg product by immersion thereof in a liquid bath at specified temperatures over a relatively short predetermined period of time.
In the commercial production of cooked egg products, such as hard boiled eggs or other hard cooked eggs and the like, it is frequently desirable to be able to store the cooked product for an extended period of time in such a manner as to preserve its physical and chemical characteristics thereby to retain the desirable characteristics of the freshly cooked product. Various methods of treating such egg products have been suggested when it is desirable or necessary to store the product for use at a later time, some of which methods have been practiced commercially.
A number of the methods of the prior art involve the use of additives of various kinds. Other methods, some employed commercially, involve the use of conventional freezing techniques, with or without additives. Most of these commercial or suggested practices of the prior art in treating the cooked product have not been satisfactory for most applications because they result in an alternation of the texture and consistency of the gel structure of the egg white to an extent which renders the white unpalatable or otherwise unsatisfactory for use in egg salads or the like.
It is known that the delicate gel structure of the cooked egg white holds substantial amounts of water. Approximately three-quarters of the water held by the gel structure formed by heat-denaturing the egg white protein is chemically free water which, under freezing techniques of the prior art, such as have been typically used in connection with the freezing of most food products, at low temperatures forms relatively large ice crystals. When such freezing is done slowly, these crystals are of sufficiently large size to disrupt the protein gel structure. Also ice crystal formation which is not uniform from the surface to the interior of the material frozen will likewise disrupt the protein gel structure. In either case, this disruption causes the release of free water, such that the egg whites upon thawing may be said to "weep." This syneresis or "weeping" results in a product which is generally unsatisfactory for consumption in such dishes as egg salad, for example.
Another manifestation of the disturbance and alteration of the gel structure resulting from the use of prior art freezing techniques is the marked change in the texture and consistency of the thawed egg white product. The tough, fibrous and/or chewy character of egg whites frozen using prior art techniques is in marked contrast to the tender and palatable character of the freshly cooked egg product, or of the egg product treated by the method of the present invention.
Other prior art attempts to create a frozen egg product comparable to the freshly cooked product have involved the addition of various chemicals prior to freezing in an attempt to alter or stabilize the gel structure present. These teachings have generally been unsatisfactory for a variety of reasons. Either the additive used must itself be edible, or means must be provided to remove it prior to consumption. In either case an added expense is incurred. Also in either case, the safety of such additives may be seriously in question.